The proposed work for the current year includes (1) the investigation of the effects of a variety of vasoactive substances on calcium transport in vascular smooth muscle isolated from normotensive, pre-hypertensive and hypertensive rats. (2) the effects of electrical stimulation and vasoactive drugs on calcium release and binding in vascular smooth muscle sarcoplasmic reticulum isolated from normotensive and hypertensive rat aortas and (3) investigation of aging and hypertension on factors which inhibit sarcoplasmic reticulum isolated from rat aortas. We will extend our investigation of relaxing systems to the hypertensive and normotensive rat. Calcium transport, binding and release will be studied in isolated rat aorta and isolated aortic sarcoplasmic reticulum. In addition, the effects of aging and hypertension on factors which inhibit calcium transport in sarcoplasmic reticulum will be investigated.